How Do CO2 Lasers Work?

David ScottUpdated February 21, 2017

A CO2 laser is a type of gas laser. This means that electricity is run through a gas to produce light. A CO2 laser has a tube filled with gas with a transparent mirror on one end, meaning that some light can get through it, and a fully reflective mirror on the other end. This gas mixture is generally comprised of carbon dioxide, nitrogen, hydrogen and helium. The beam produced by a CO2 laser is emitted through the transparent mirror.

Composition

A CO2 laser is a type of gas laser. This means that electricity is run through a gas to produce light. A CO2 laser has a tube filled with gas with a transparent mirror on one end, meaning that some light can get through it, and a fully reflective mirror on the other end. This gas mixture is generally comprised of carbon dioxide, nitrogen, hydrogen and helium. The beam produced by a CO2 laser is emitted through the transparent mirror.

Production of the Laser Beam

When electricity is run through the gas mixture, the particles of nitrogen become excited, meaning that they gain more energy. Nitrogen is used because it can hold this excited state for long periods of time without discharging the energy in the form of photons, or light. The excited vibrations of the nitrogen then cause the carbon dioxide to become excited as well. At this point, population inversion has been achieved. Population inversion is the point at which a system has more excited particles than non-excited particles. For the laser to produce a beam of light, the nitrogen atoms must lose their excited state by releasing energy in the form of photons. This is achieved when the excited nitrogen atoms contact the very cold helium atoms, which causes the nitrogen to discharge light.

The light produced is so powerful compared to normal light because the tube of gases in a laser beam is surrounded by mirrors, which serve to reflect at least part of the light travelling through the tube. This reflection of light causes the light waves being produced by the nitrogen to reinforce themselves. This means that the light is amplifying as it travels through the gas tube, only coming out after reaching a certain intensity, making it extremely powerful.

Laser Beam

The laser beam discharged by the formerly excited nitrogen atoms is in the infrared part of the spectrum. The laser produced in this method is powerful enough to cut many substances and also destroy many others. Because it's in the infrared, it has a very high wavelength, around 10.6 micrometers. As a continuous laser, this laser beam is the most powerful in production.

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About the Author

David Scott has been a firefighter for the Seattle Fire Department's Technical Rescue Team for almost 20 years. He has been writing primarily since 2005, but did author the book, "The White River Ranger District Trail Guide" in 1988. In addition to his work for Demand Studios, Scott spends much of his time writing poetry and a novel.